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Biomedical subjects

M Cowan

Publications and source records attributed to M Cowan.

At least 37 records · Page 2Linked to original sources
PubMed1994

Aminosulfonic acid buffer preserves myocardium during prolonged ischemia.

Prevention of myocardial acidosis during global ischemia in operative cardiopreservation was explored in two series of dogs where acid-base control was the only variable. A specifically designed aminosulfonic acid buffer composition, 3:1 molar equivalents NaMOPS to HEPES, 0.2 mol/L, was compared with NaHCO3 (pH 8). Dissolved in standard cardioplegic solution it was given every 30 minutes by coronary infusion at 20 degrees C during 3 hours of global ischemia. Glass electrode intramyocardial pH, adenosine triphosphate (ATP) level, left ventricular contractility (Dp/Dt) and compliance (-Dp/Dt), and other cardiovascular parameters were measured frequently throughout ischemia and for 75 minutes thereafter. In the buffer group (n = 6) myocardial pH remained above entry levels throughout the study period, adenosine triphosphate level remained normal during ischemia, and Dp/Dt and -Dp/Dt at 75 minutes of reperfusion were above entry levels. In the NaHCO3 group (n = 6) pH declined and remained depressed throughout ischemia, adenosine triphosphate level fell steadily and significantly throughout the experiment, and Dp/Dt and -Dp/Dt never regained entry levels. The difference in each parameter between the two groups was statistically significant (p < 0.05). We conclude that control of myocardial acid-base equilibrium alone during global ischemia will preserve myocardial function and minimize reperfusion injury.

Acidosis↗
PubMed1994

Nycthemeral profile of nonspectral heart rate variability measures in women and men. Description of a normal sample and two sudden cardiac arrest subsamples.

Heart rate variability (HRV), a noninvasive systemic index of the central autonomic nervous system, demonstrates considerable within-subject variability, including a strong systematic 24-hour nycthemeral (or less precisely, circadian) component. Recent interest in the timing of sudden cardiac arrest (SCA), especially the pronounced morning rise in sudden deaths, has motivated research into coincident dynamic phenomena in HRV indices of central autonomic nervous system activity. In this study, statistical (nonspectral) HRV measures (SD and %RR50) were summarized for consecutive 15-minute blocks from 24-hour Holter electrocardiogram tapes. Six subgroups were scrutinized: women and men respectively in three clinical strata (normal subjects [n = 85 women and 40 men], SCA with no current or prior myocardial infarction [MI] [n = 9 women and 31 men], SCA with old MI [n = 7 women and 48 men]). Significant nycthemeral effects were observable for all HRV measures in five of the six groups, with a dramatic fall in HRV during the hours of the morning with the highest phenomenologic incidence of SCA. Both strata of SCA subjects had much lower HRV than the normal subjects. This effect was strongest during the night-time hours, particularly for a purported index of vagal tone (%RR50). For reasons that are not known, the nine female SCA survivors who had no current or previous MI presented very distinct 24-hour patterns for the HRV measures studied. Twenty-four-hour profiles of short-term statistical HRV provide a rich field for the observation of within-subject adaptations of the central autonomic nervous system inputs to the heart in both normal and clinical subgroups.

Circadian Rhythm↗
PubMed1994

Diagnosing and managing unstable angina. Agency for Health Care Policy and Research.

This Quick Reference Guide for Clinicians contains recommendations on the care of patients with unstable angina based on a combination of evidence obtained through extensive literature reviews and consensus among members of an expert panel. Principal conclusions include the following. (1) Many patients suspected of having unstable angina can be discharged home after adequate initial evaluation. (2) Further outpatient evaluation may be scheduled for up to 72 hours after initial presentation for patients with clinical symptoms of unstable angina judged at initial evaluation to be at low risk for complications. (3) Patients with acute ischemic heart disease judged to be at intermediate or high risk of complications should be hospitalized for careful monitoring of their clinical course. (4) Intravenous thrombolytic therapy should not be administered to patients without evidence of ST segment elevation and acute myocardial infarction. (5) Assessment of prognosis by noninvasive testing often aids selection of appropriate therapy. (6) Coronary angiography is appropriate for patients judged to be at high risk for cardiac complications or death based on their clinical course or results of noninvasive testing. (7) Coronary artery bypass surgery should be recommended for almost all patients with left main disease and many patients with three-vessel disease, especially those with left ventricular dysfunction. (8) The discharge care plan should include continued monitoring of symptoms; appropriate drug therapy, including aspirin; risk-factor modification; and counseling.

Ambulatory Care↗
PubMed1993

Wegener's granulomatosis. Typical symptoms in an atypical patient.

Wegener's granulomatosis classically involves the respiratory tract and kidneys, and the disorder may be confused with any of a number of diseases having similar symptoms. Although most common in middle-aged whites, Wegener's granulomatosis may occur in atypical patients, as in the case described here. Accurate diagnosis depends on lung biopsy, and prompt treatment prevents permanent damage and significant sequelae.

Adult↗
PubMed1993

Flow chamber study of the adhesion of Prevotella intermedia to glass after preconditioning with mutans streptococcal species: kinetics and spatial arrangement.

The adhesion kinetics and spatial arrangement of a clinical isolate of Prevotella intermedia on bare glass and on glass which had been previously exposed to Streptococcus rattus or Streptococcus cricetus were studied using a parallel plate flow system and image analysis. When S. cricetus was the preconditioning organism the initial deposition rate and efficiency of P. intermedia were reduced even though very few S. cricetus adhered during flow with P. intermedia. Preconditioning with S. rattus had less effect on the adhesion behaviour of P. intermedia despite the fact that more S. rattus cells adhered than S. cricetus cells. Small differences in both the stationary state adhesion and in the final spatial arrangements were evident under the three experimental conditions. S. cricetus negatively influences initial deposition of subsequent P. intermedia adhesion possibly by the production of a biosurfactant or by leaving 'microbial footprints'. This interference is eventually overcome resulting in a similar stationary state adhesion of P. intermedia as found without S. cricetus preconditioning. Furthermore, the flow chamber system employed here proved uniquely suited for studying cell-cell interactions in initial adhesion.

Bacteria, Anaerobic↗
PubMed1992

Microgranulomatous aspergillosis after shoveling wood chips: report of a fatal outcome in a patient with chronic granulomatous disease.

Chronic granulomatous disease is characterized by recurrent infections that result from an inability of phagocytes to kill organisms effectively. We describe a patient with this disease who developed aspergillus pneumonia after shoveling moldy cedar wood chips. Despite aggressive therapy, the patient's condition deteriorated and he died. At autopsy, the lungs revealed diffuse granulomas, all of the same age, with aspergillus organisms confined to the granulomas. We propose the term "microgranulomatous aspergillosis" for this response, which does not conform to the commonly described aspergillus syndromes. We conclude that susceptible immunosuppressed patients should be advised to avoid occupational situations where high spore concentrations are generated.

Adult↗
PubMed1991

Infectious enthusiasm.

Explore the source record for details and available documents.

Ancillary Services, Hospital↗
PubMed1991

Developmental intervention in the newborn intensive care unit.

Developmental intervention for infants with perinatal asphyxia requires an individualized therapeutic plan. A team approach incorporating developmental goals and intervention strategies into the nursing care of these infants is essential for optimal developmental outcome. Therapeutic management must always be appropriate for the infant's health status, gestational age, and organizational capabilities. An understanding of the neurophysiologic basis for intervention and the therapeutic management techniques for infants who are sick, recuperating, or convalescing will help the nurse to promote optimal development when caring for the asphyxiated infant.

Asphyxia Neonatorum↗
PubMed1990

Inhibition of rate of tumour growth in rodent species by inoculation of herpesviruses and encephalomyocarditis virus.

Inoculation of herpesviruses and encephalomyocarditis virus into subcutaneous tumours in hamsters and mice reduced the rate of tumour growth compared to untreated tumours or secondary tumours which had arisen following surgical excision of the primary tumour; in addition, survival times were increased in animals whose tumours were inoculated with virus. It is suggested that the role of virus in the modification of tumour growth merits further exploration.

Animals↗
PubMed1988

Inhibition of some spontaneous tumors by 4-hexylresorcinol in F344/N rats and B6C3F1 mice.

4-Hexylresorcinol (4-HR) is used as an anthelmintic and antiseptic in human and veterinary medicine. Toxicology and carcinogenesis studies were conducted by administering 4-HR in corn oil by gavage at 0, 62.5, or 125 mg/kg to F344 rats and B6C3F1 mice of each sex for 2 years. The nonneoplastic lesions associated with 4-HR exposure were nephropathy and osteosclerosis in dosed male and female mice. The only evidence of neoplasia associated with 4-HR was marginally increased incidences of adrenal gland pheochromocytomas and harderian gland tumors in male mice. Decreases were observed in the incidences of mononuclear cell leukemia in dosed male and female rats, hepatocellular adenomas or carcinomas in dosed male mice, and circulatory system tumors in high-dose male and female mice. These negative tumor trends in rats and mice, along with an indication of reduced overall incidences of benign and malignant tumors in treated groups compared to controls, suggest that 4-HR may deserve further study as a possible antineoplastic agent.

Animals↗
PubMed1988

Reduced tumorigenicity of rodent tumour cells and tumour explants following infection with wild type and mutant herpes simplex virus, bovine mammillitis virus and encephalomyocarditis virus.

The tumorigenicity of neoplastic hamster and mouse cell lines and tumour explants was reduced by infection with herpes simplex virus (HSV-1), a thymidine-kinaseless mutant of herpes simplex virus, namely 'MDK', encephalomyocarditis virus (EMC) and bovine mammillitis virus (BMV). There was an approximate relationship between duration of virus infection in vitro and reduction in incidence and/or rate of tumour development. The rate of tumour development was also reduced by 'site inoculation' of virus (HSV-1) at various time intervals following inoculation of tumorigenic BHK 21 cells indicating that virus was capable of reducing the rate of tumour development in a situation where the neoplastic cells were already transplanted into the susceptible host species. It is suggested that the therapeutic role of wild type, mutant or recombinant viruses merits further exploration towards prevention and treatment of human cancer.

Animals↗
PubMed1987

Follow-up report on 50 subjects vaccinated against herpes genitalis with Skinner vaccine.

Fifty subjects at risk of herpes genitalis received 109 immunizations with Skinner herpes vaccine and were assessed after a follow-up period of 4-48 months, representing a total follow-up period of 694 patient months. There was no evidence of contraction of herpes genitalis in 49 subjects. The risk of virus transmission and rate of contraction of disease was quantified by construction of two functions, namely a unit of exposure risk calculated per year (UYE) and standard contraction rate (SCR); in this study the SCR was 0.02. There was no evidence of significant side-effects from vaccination. Administration of Alhydrogel adjuvant with vaccine induced temporary granuloma formation in most subjects but was only detectable beyond 1 year of follow-up in one subject, in whom a painless swelling of 0.2 cm was detected 3 years after vaccination. There was no evidence of immunological reactivity to host cell or calf serum antigens in any of the subjects vaccinated.

Adolescent↗
PubMed1987

Role of bovine mammillitis virus towards preparation of an alternative vaccine against herpes simplex virus infections of human subjects.

Bovine mammillitis virus (BMV) cross-reacted in neutralization and radioimmune assay with herpes simplex virus (HSV) and pre-immunization with BMV protected against challenge by type 2 HSV. There was no evidence to suggest a pathogenic role for BMV as adjudged by a literature search or field enquiry and BMV specific antibody was not detected in 21 human sera or in four sera from personnel engaged in research with BMV; in addition there was no replication or antigen synthesis by BMV in explants of human tissue or cell lines of human origin. It is proposed that BMV might provide an alternative vaccine against HSV infections of human subjects.

Animals↗
PubMed1987

Perforated stomach following the Heimlich maneuver.

The use of infradiaphragmatic abdominal pressure for relief of airway obstruction caused by food was first described by Henry Heimlich in 1974. Since that time, several complications have been reported. We report a case of gastric perforation occurring in a choking victim following the application of the Heimlich maneuver.

Aged↗
PubMed1987

Estimation of myocardial infarct size by electrocardiographic and radionuclide techniques.

The Western Washington Intravenous Streptokinase in Acute Myocardial Infarction Trial was a randomized, experimental, multicenter clinical study comparing intravenous streptokinase therapy to conventional therapy of acute myocardial infarction. Myocardial infarct size was estimated by spatial vectorcardiography in 93 patients in the treatment group and 80 patients in the control group eight weeks post MI. The estimated infarct size for the treated group was smaller: 16 +/- 10% MI vs. 20 +/- 9% MI for the control group, P = 0.01. Four independent techniques to estimate infarct size were prospectively compared within the same day: Cowan's spatial VCG; the Selvestor/Wagner QRS score; 99m technetium synchronized ejection fractions and 201-Thallium Tomography. There was strong correlation between the two ECG techniques (r = 0.88) and between the two radionuclide techniques (r = 0.77). Statistically significant correlations (P = 0.0001) were described, respectively, among the four techniques, but the correlations were not clinically strong between electrocardiographic and radionuclide techniques: IAD vs. EF, r = -0.41; IAD vs. 201-Tl, r = 0.50; QRS Score vs. EF, r = -0.49; QRS Score vs. 201-Tl, r = 0.58.

Clinical Trials as Topic↗
PubMed1987

Risk of AIDS for recipients of blood components from donors who subsequently developed AIDS.

Reported cases of acquired immunodeficiency syndrome (AIDS) in San Francisco as of March 31, 1986, include 92 individuals who had donated blood subsequent to 1978. Their donated blood components had been transfused into 406 different recipients. The current status of 336 of these recipients was ascertained as of April 1, 1986. Of these, 223 had died at the time of our first contact, almost all as a result of the condition for which they were transfused. Seven had developed AIDS; five of these died, two before entry into the study and three subsequently. Forty-six additional living recipients were interviewed and evaluated. Seven had the AIDS-related complex, 18 had antibody to the human immunodeficiency virus (HIV) but were otherwise healthy, and 19 had no detectable anti-HIV. Two had risk factors other than transfusion. The frequency of infection of the recipient decreased as the time interval between transfusion and the diagnosis of AIDS in the donor increased. This information should be useful when counseling patients who have been transfused with blood components from donors later found to be infected with HIV.

Acquired Immunodeficiency Syndrome↗